Aqueous lubricating compositions

ABSTRACT

AN AQUEOUS LUBRICATING COMPOSITION CONSISTING ESSENTIALLY OF AN AQUEOUS CARRIER CONTAINING FROM ABOUT 5 TO ABOUT 40 PERCENT BY WEIGHT OF A BLEND OF   (A) AN N-ACYLSARCOSINATE SURFACTANT AND (B) AN N-ACYL-N-ALKYLTAURATE SURFACTANT   WHEREIN THE WEIGHT RATIO OF (A) TO (B) IS IN THE RANGE OF FROM ABOUT 0.25 TO ABOUT 4.0.

nited States Patent 01 ice;

3,766,668 Patented Oct. 16, 1973 3,766,068 AQUEOUS LUBRICATING COMPOSITIONS Thomas C. Tesdahl, Forest Park, Douglas L. Holcer,

Fairfield, and Homer E. Crotty, Cincinnati, Ohio, assignors to W. R. Grace & Co., New York, N.Y. No Drawing. Filed Nov. 20, 1970, Ser. No. 91,530 Int. Cl. C10m 3/34, 3/30 US. Cl. 25233.2 8 Claims ABSTRACT OF THE DISCLOSURE An aqueous lubricating composition consisting essentially of an aqueous carrier containing from about to about 40 percent by weight of a blend of (a) an N.-acylsarcosinate surfactant and (b) an N-acyl-N-al-kyltaurate surfactant wherein the weightratio of (a) to (b) is in the range of from about 0.25 to about 4.0.

This invention relates to aqueous lubricating compositions and, in particular, to aqueous compositions for lubrication of chain conveyors.

In the past, solutions of fatty acid soaps have been used for aqueous lubrication of contacting metal-to-metal and metal-to-glass surfaces in chain conveyors (by which term is meant conveying equipment such as that illustrated and described in Kirk-Othmer, Encyclopedia of Chemical Technology, 2d ed., vol. 6, 1965, pages 102 and 109-110 Drag Chain and Flight Conveyors). The use of soft water or chemically sequestered water is required in preparing aqueous fatty acid soap lubricating compositions in order to inhibit or prevent formation of undesirable calcium soap curd on the conveying equipment. This prior art problem, together with improved design and faster chain speeds in modern day chain conveyors have led to the need for new and improved aqueous lubricating compositions.

It is an object of this invention to provide new and improved aqueous lubricating compositions characterized by absence of scum or curd deposits, low foam, and hard water tolerance. Other objects and advantages of the invention will be apparent from the following more detailed description thereof.

In accordance with the present invention it has been discovered that the foregoing objectives can be attained by lubricant compositions consisting essentially of an aque ous carrier containing from about 5 to about 40 percent by weight, based on total weight, of a blend of:

(a) An N-acylsarcosine surfactant having the formula 0 R-li-N-CHiCH: S 0 3X wherein the acyl group is the residue of a fatty acid having from about 10 to about 20 carbon atoms; X is hydrogen, alkali metal (e.g., lithium, sodium, potassium) or ammonium (NH.,+) and R is an alkyl or cycloalkyl group having from 1 to 6 carbon atoms. The acyl group and X in the two surfactants may be the same or different.

The aqueous carrier of the compositions of this invention is usually water but may comprise water together with relatively minor amounts, e.g., up to about 10% by weight based on the total weight of the lubricant composition, of a water miscible co-solvent such as ethanol, isopropanol, propylene glycol, hexylene glycol, butyl Cellosolve (i.e., ethylene glycol monobutyl ether) and other similar type solvents.

The sarcosine surfactants used in the practice of this invention are known, per se, in the art. A number of suitable sarcosinate surfactants are commercially available. Representative of this class of surfactants are lauroyl sarcosine, cocyl sarcosine, oleoyl sarcosine, stearoyl sarcosine, tall oil acyl sarcosine and the corresponding alkali metal or ammonium sarcosinates. The preferred sarcosine surfactant is one in which the acyl group has from 14 to 18 carbon atoms, especially sodium or potassium N-oleoyl sarcosinate.

The taurine surfactants used in the compositions of this invention are likewise known, per se, in the art. Representative suitable examples of taurine surfactants are N- methyl-N-acyl taurine wherein the acyl group is oleoyl, cocoyl, palmitolyl, tall oil acyl, or tallow acyl; the corresponding N-cyclohexyl-N-acyl taurines such as N-cyclohexyl N-palmitolyl taurine; and the corresponding sodium or potassium taurates of any of the foregoing. A number of these materials are also commercially available. The preferred taurine surfactant is sodium or potassium N- methyl-N-oleoyl taurate.

The weight ratio of the sarcosine surfactant to the taurine surfactant is in the range of from about 0.25 to about 4.0, and preferably from about 1.0 to about 3.0, for example 2.5.

The compositions of the invention are normally prepared as aqueous concentrates containing from about 5 to about 40 weight percent, preferably about 10 to about 25, e.g., 20 weight percent, dry solids basis, of the sarcosine-taurine surfactant blend, based on total weight of the composition. In use such concentrates are diluted with additional water in amounts of from about 1 to 200 parts by volume of water per part by volume of concentrate at the point of use as a lubricant. Preferably the dilution volume ratio is from about 25 to 100.

Other ingredients which may be included in the concentrates in relatively minor amounts of up to about 20 weight percent each, based on total weight of the composition, are:

corrosion inhibiting agents such as volatile amine corrosion inhibitors (cyclohexylamine, benzylamine, morpholine, etc.) or lower alkanol amines (hydroxyethyl amine, monoisopropanol amine) or ammonium hydroxide;

chelating agents for product clarity control, for example ethylenediamine-tetraacetates (commonly referred to as E.D.T.A.), nitrilotriacetates (NTA), methylene diphosphonates, amino tri(methylene phosphonates) and the like.

,. alkali for pH adjustment to pH 6-12 preferably 8-12;

e.g., free sodium or potassium hydroxide;

free-fatty acid soapy-egg potassium or sodium laurate,

oleate, stearate, etc.

Thus the concentrates of this invention are those which include:

It will be understood that the amounts of sarcosinate and taurate within the ranges stated are chosen in all cases to provide the requisite weight ratio of 0.25 to 4.0, preferably about 2.5.

The invention is further illustrated by the following representative examples:

EXAMPLES 1 AND 2 These examples illustrate composition within the scope of the invention and in the form of liquid concentrates.

Percent by weight Ingredient Composition Ex. 1 Ex. 2

1 Oleoyl sarcesine (94% active solids) 10. 10. O 2 Sodium N -methyl-N -oleoyl taurate (32% 13. 0 9. 0

active solids). 3 E.D.T.A. (40% solution) 0. l 0. 1 4- Caustic potash (40% solution) 4. 0 4. 0 5 Monoisopropanolamme 1. 0 1. 0 6 Water Balance Balance Procedure:

( 1) Add items 1, 2 and 3 to the water with good agitation. (2) Add caustic slowly, adjust pH to 9.0. (3) Add amine.

EXAMPLES 3 AND 4 These examples illustrate gel-type concentrates of compositions within the scope of the present invention.

Percent by weight Ingredlent Composition Ex. 3 Ex. 4

1 Oleoyl sarcosine (94% active solids) 21.0 10 2 Sodium N-rnethyl-N-oleoyl taurate (32% 20.0

active solids).

3 E.D.T.A. (40% solution) 0.1 0 1 4- Caustic potash (46% solution) g- Monoisopropanolamine 1 Procedure: (1) Same mixing procedure as in Examples 1 and 2.

What is claimed is:

1. Aqueous lubricating composition consisting essentially of an aqueous carrier containing from about 5 to about 40 percent by weight based on total weight, of a blend of I v O R- N-CH; C 0 OX together with (b) a taurine surfactant having the formula group in the two surfactants is, independently, the residue of a fatty acid having from about -12- to about 20 carbon atoms; X is, independently, hydrogenalkali metal or ammonium and R is an alkyl or cycloalkyl group having from 1 to about 6 carbon atoms;

the weight ratio of (a) to (b) being in the range of from about 0.25 to about 4.0. p

2. Composition as defined in claim 1 wherein the ratio of (a) to (b) is about 2.5.

3. Composition as defined in claim 2 wherein the sarcosine surfactant is an alkali metal N-oleoyl sarcosinate.

' 4. Composition as defined in claim 2 wherein the taurine surfactant is an alkali metal N-methyl-N-oleoyl taurate.

5. Composition as defined in claim 1 wherein the aqueous carrier is water. p

6. Composition as defined in claim 1' wherein the aqueous carrier is a mixture of water and up to 10 weight percent, based on total weight of the composition, of a co-solvent selected from the group consisting of ethanol, isopropanol, a lower alkylene glycol having up to 6 carbon atoms, mono-lower alkyl (C to C ethers of said alkylene glycols, or mixtures thereof.

7. Method for lubricating a chain conveyor comprising applying thereto a solution consisting essentially of about 1 part by volume of a composition as defined in claim 1 in about 1 to about 200 parts by volume of water of dilution.

8. Method for lubricating a chain conveyor comprising applying thereto a solution consisting essentially of about 1 part by volume of a composition as defined in claim 2 in about 25 to about parts by volume of water of dilution.

wherein the acyl References Cited UNITED STATES PATENTS 2,951,039 8/1960 Salisbury et al. 252--33.3 3,259,577 7/1966 Coant et al. 25233.3 2,790,779 4/ 1957 Spivack et a1. 25233.4 2,841,555 7/1958 Lyons et al. 252-33.4 3,594,411 7/1971 Kite et al. 252-33.4 3,046,225 7/ 1962 Murray et al. 252-336 3,412,023 11/1968 Zuraw et al. 252-332 3,574,100 4/1971 Wetmore 252-33.6

DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner 

